SetInScenePlaced marks runtime instantiated NetworkObjects as InScenePlaced

[ffejlersen]

Description

A clear and concise description of what the bug is.

Reproduce Steps

1. Go to 'NGO_Setup'
2. Start play mode
3. Click on 'Start Host'
4. Click on the keyboard button "L" to load an additive scene with a spawner object
   • Console prints instance InScenePlaced state as False
5. Click on the keyboard button "D" to print current state of spawned object

• Console prints instance InScenePlaced state as True

Expected Outcome

Network objects instantiated during runtime should not be marked as InScenePlaced = true.
Before the introduction of SetInScenePlaced it was allowed to instantiate network objects from Awake.

Environment

• OS: Windows 11
• Unity Version: 6000.3.6f1
• Netcode Version: 2.13.1
• Netcode Topology: Client-Server

Unity Project

UnityProject.zip

[NoelStephensUnity]

Hi @ffejlersen,

Thank you for your submission and the replication project as it greatly helped me narrow down the issue.

If you dynamically instantiate something and then immediately disable the root GameObject, in order for any netcode related property to be accurate you will need to make sure:

• The root GameObject is active in the hierarchy.
• The NetworkObject has been spawned.

Make this adjustment in your FooSpawner:

    private void Update()
    {        
        if (Keyboard.current.dKey.wasPressedThisFrame)
        {
              // Enable it.
            _instance.gameObject.SetActive(true);

             // Spawn it.             
            _instance.GetComponent<NetworkObject>().Spawn();

            // Log the netcode fields or properties you want to check
            Debug.Log($"{_instance.name} now has in-scene-placed value of: {_instance.GetComponent<NetworkObject>().InScenePlaced}");
        }
    }

The related values of things that could be calculated during the spawn process are most likely not going to be accurate until it is spawned. The in-scene placed flag you are seeing when it is still disabled and not spawned lets us know you have pre-instantiated something into a scene, that is most likely still loading, and that (along with other information) allows us to determine that it should be treated as a dynamically spawned object. Once it is spawned, it should reflect the correct values.

Let me know if this resolves your issue?

[ffejlersen]

Just to clarify our use-case.
We have our own pooling implementation with NGO. We are seeing this, when we pre-warm our pools that are constructed before the IProcessSceneWithReport.OnProcessScene is invoked, but when the scene has been loaded.

I haven't tried the suggested solution, but it seems to set the instances as active and spawns them? I guess they aren't ready for being spawned, since they are already marked as spawned?

We have currently solved it by delaying the creation of them, or by providing a separate scene for inactive instances.

[EmandM]

Delaying the creation is a solid solution here.

To explain what is going on here. We updated the marker of whether or not an object is "in the scene" from a nullable boolean to a boolean. The previous nullable boolean wasn't calculated until the object was first spawned which meant some of the edge case handling of "in scene placed" objects was inaccurate. That inaccuracy is why the SetInScenePlaced() function existed.

As you've noticed, we moved the calculation from when the object is spawned to the IProcessSceneWithReport.OnProcessScene. The issue is, in the editor only, OnProcessScene will run after Awake has run on all objects in the scene. We were able to add checks to ensure we don't process any disabled object that is created in Awake. We also are able to skip any object that is created in a different scene and then moved into the current scene being processed.

We're talking with the build team about providing a similar callback that doesn't run Awake first in the editor. They are working on it, but the CoreCLR related build changes are taking precedence at this time.

We would be open to adding an equivalent to SetInScenePlaced that simply marks an object to be skipped by the OnProcessScene post-processor? We made this change hoping that manual configuration on the InScenePlaced variable wouldn't be needed. If it is needed then there's no reason to not add it back in.

[ffejlersen]

It is a bit of a hassle, since it introduces issues in the editor that isn't immediately evident about why it happens. It requires a bit of digging into the code to find the culprit.

However, we just have to be aware that we aren't allowed to do any instantiation of network objects in Awake right after the scene has loaded.